1. Field of the Invention
This invention relates to seats, and more particularly, to seats having a mechanism for selectively adjusting the height thereof.
2. Description of the Prior Art
There are many instances in which it is desirable that the height of a seat be selectively adjustable, according to the needs of the user. Accordingly, it is not surprising that there are many prior art devices which address themselves to providing such a seat.
Perhaps the simplest form of height adjustable seat is that disclosed by U.S. Pat. No. 3,230,910 granted Jan. 24, 1966, to Olsson, which comprises a conical base having a recess on the top thereof which receives a downwardly projecting cone depending from the seat. The height of the seat may be adjusted by interposing an intermediate member between the base and the downwardly projecting cone on the seat.
U.S. Pat. Nos. 2,218,963, granted Oct. 22, 1940, to Stephenson; 2,446,127, granted July 27, 1948, to Cramer; and 2,505,100, granted Apr. 25, 1950, to Cramer, disclose height adjustable stools in which the height of the stool is selected by use of a relatively complex and costly hydraulic apparatus.
U.S. Pat. Nos. 397,851, granted Feb. 12, 1889, to Gifford; 581,486, granted Apr. 27, 1897, to Monkiewicz; and 848,465, granted Mar. 26, 1907, to Homeyer disclose collapsible chairs or stools in which the height of the chair or stool is adjusted by folding hinged support members in selective amounts.
U.S. Pat. No. 2,600,735, granted June 17, 1952, to Corneliussen et al discloses a height adjustable seat in which a movable inner column, which supports the seat, is selectively locked with respect to the outer column by means of a locking disc 4, carried by the outer column, which encircles and selectively engages the inner column with a friction grip.
U.S. Pat. Nos. 3,737,136, granted June 5, 1973, to Snurr, and 3,741,514, granted June 26, 1973, to Snurr, each disclose a height adjustable support utilizing three concentric shafts. The inner and outer shafts are secured to a base while the middle shaft supports a seat and carries a locking device for height adjustment. In the first patent, the locking device comprises locking balls 25, contained within a tapered bore in a locking body 20, which frictionally engage the center shaft when weight is applied to the seat. In the second patent, the locking device comprises a wedge locking device 22 which also uses locking balls 32 as previously described.
U.S. Pat. No. 942,975, granted Dec. 14, 1909, to Porter, discloses a device for a shoe salesman comprising a footrest connected to the support post for a seat in such a way that when the seat is depressed, as by the weight of a person sitting on it, the footrest is elevated for use. The seat may be locked in positions of varying heights by means of detents 12 which selectively engage the notches 11 on the support post. The detents are carried by the column which encircles the support post.
U.S. Pat. No. 1,016,763, granted Feb. 6, 1912, to Nill, discloses a stool whose height is adjustable by selectively engaging the notches 20 in the supports 19 with the pins extending from the arms 15, 16. The pins pass through openings 11 in the legs 1 which enclose the supports.
U.S. Pat. No. 740,120, granted Sept. 29, 1903, to Graefe, discloses a height adjustable stand for flower pots in which a tooth 8 on a yoke-like lever 7, carried by a standard 2, selectively engages the stem's teeth 5 through the slot 6 in the standard 2.
U.S. Pat. No. 264,458, granted Sept. 19, 1882, to Johnson, discloses a height adjustable piano stool having two pairs of pivotally interconnected legs A and G between which is supported a cross member B. Cross member B supports an upwardly extending toothed shaft E about which a casing D extends. Casing D supports a lever H whose lower end d is arranged to selectively engage the notches e in the post d.